Valves in pipeline or flow conduits are commonly used to control fluid flow through a conduit and can include a rotatable valve element in a valve body where the valve element can be rotated between positions of open and closed conditions of the valve and typically involve a ninety degree rotation of a valve stem. In some circumstances the valve element is rotated through 180.degree. or 270.degree.. The valve stem is rotated through the ninety degrees (or other angle) by a valve actuator which can be hydraulic, pneumatic, mechanical, manual or the like to rotate the valve between its open and closed position. The valve actuator can be locally or remote controlled.
The valve actuator and the valve are respectively bolted to a support base member. A typical support base member has a hollow interior in the form of a rectangular cross-section. The valve actuator typically has a square, or non-circular shaped, actuator shaft extending into the hollow interior. Similarly, the valve has a square, or non-circular shaped, valve stem shaft extending into the hollow interior. The actuator and valve stem shafts are axially aligned. A coupling device or sub with square shaped socket ends is used to connect the valve actuator shaft to the valve stem shaft so that rotation of the valve actuator shaft is transmitted to the valve stem shaft to move the valve stem between the open and closed positions. In other instances, the support base member can be a solid plate with a hole for the shafts and coupling member. Other types of support will be known to those skilled in the art.
In many instances, by governmental regulation and otherwise, it is desirable to provide security in the form of a locking mechanism to lock a valve in either an open or closed position which prevents unauthorized and unintended operation of the valve. Heretofore, with the apparatus as described above, the system for locking has involved the drilling of a bore through the coupling member and through the support base member and utilizing a rod type locking member which must be aligned precisely with the bores for locking purposes. This type of system is an expensive and awkward type of modification and involves particular alignment problems which do not make it readily advantageous to utilize.